Letterbox lyrics

I'll never know what you'll find when you open up your letter box tomorrow
'Cause a little bird never tells me anything I want to know, she's my best friend, she's a sparrow
And I'll never never know what you never never never want to know when you know what you are, O.

If I had a pair of eyes on the back of my head for each time
You forgot to take out all the things you forgot to talk about when you took a bite out of my spine,
I would have a lot of eyes on me by this time wouldn't I? Wouldn't that just be fine.

Too late or soon to make noise about* love and there's no time for sorrow
Run around in the rain with a hole in the brain till tomorrow

I'll never know what you'll find when you open up your letter box tomorrow
'Cause a little bird never tells me anything I want to know, she's my best friend, she's a sparrow
And I'll never never know what you never never never want to know when you know what you are, O.

Submitted by Guest

What do you think is the meaning of Letterbox by They Might Be Giants?